Nothing is trivial when you are talking about safety and learning! Ask away!
Water depends on your tires, slicks yes, street treaded, not so good. Each track is different, so ask the track staff.
As for the starting, Understand that your first few trys will not cause the top fuel teams to offer you a contract and millions, so just try to be safe and not do anything stupid. It's quite alright to go sit in your car in the garage and visualize the whole process. Helmet on helps too.
When you leave your pit area, you and the car should be ready to run. When you pull up to the front of the line, you should be watching the track guy for what to do (hopefully, you have already talked and he knows that you are new).
When you are in the burnout area, don't do anything until the track guy signals (watch a few races to see what he does). When you pull up to the line, watch the starter, keep the car straight and then watch the prestage lights. When both your and the other car's prestage are lit, either can stage. Pull forward carefully, it's only a few inches. Try not to go too deep, causing the prestage to go out. When both are staged, the starter will press the button and the tree will count down, sending you off. Just as you cross the finish line, let off and apply the brakes. Find out before hand what the track etiquette is for who goes into the turn off first. Usually it's whoever is first down there.
Pull off and go to the timing area and pick up your time slip. (you did check where it is, right?)